The coordination of tBuPONOP (tBuPONOP = 2,6-bis(ditertbutylphosphinito)pyridine) to different ruthenium starting materials, to generate (tBuPONOP)RuCl2, was investigated. The 16-electron species (tBuPONOP)Ru(H)Cl was produced from the reaction of triethylsilane with (tBuPONOP)RuCl2. Reactions of (tBuPONOP)RuCl2 with both phenylsilane or diphenylsilane afforded the 16-electron hydrido-silyl species (tBuPONOP)Ru(H)(PhSiCl2) and (tBuPONOP)Ru(H)(Ph2SiCl), respectively. Reactions of all three of these complexes with silver triflate afforded the simple salt metathesis products of (tBuPONOP)Ru(H)(OTf), (tBuPONOP)Ru(H)(PhSiCl(OTf)), and (tBuPONOP)Ru(H)(Ph2Si(OTf))...

A triple-flow electromembrane extraction (EME) probe was developed and coupled directly to electrospray-ionization mass spectrometry (ESI-MS). Metabolic reaction mixtures (pH 7.4) containing drug substances and related metabolites were continuously drawn (20 μL/min) into the EME probe in one flow channel, and mixed inside the probe with 7.5 μL min(-1) of 1 M formic acid as make-up flow from a second flow channel. Following this acidification, the drug substances and their related metabolites were continuously extracted by EME at 400 V, across a supported liquid membrane (SLM) comprising 2-nitrophenyl octyl ether (and for some experiments containing 30% triphenyl phosphate (TPP)), and into 20 μL min(-1) of formic acid as acceptor phase, which was introduced through a third flow channel...

A simple, specific, sensitive and rapid LC-ESI-MS/MS method has been developed and validated for the quantification of 4-methylpyrazole in dog plasma using N-methylnicotinamide-d4 as an internal standard (IS) as per regulatory guideline.s Sample preparation was accomplished through a simple protein precipitation. Chromatographic separation of 4-methylpyrazole and the IS was performed on a monolithic (Chromolith RP-18e) column using an isocratic mobile phase comprising 0.2% formic acid in water and acetonitrile (20:80, v/v) at a flow rate of 1...

Da-Huang-Gan-Cao decoction (DHGCD), which is a classic formula in traditional Chinese medicine, has been clinically used for the treatment of vomiting, constipation, pancreatitis, and cholelithiasis in China and Japan. In this study, a rapid and validated method using HPLC coupled with triple quadrupole MS was developed for the simultaneous determination of 13 components in DHGCD. Separation was performed on an XBridge BEH C18 column (50 × 2.1 mm, 2.5 μm) with a gradient elution of acetonitrile and 0.1% formic acid in water...

Triazoles chanced the prevention and treatment of invasive fungal infections, but their pharmacokinetic properties are still unclear. In particular, isavuconazole (ISC) is a new broad-spectrum antifungal triazole approved in 2015 as first-line treatment for intravenous and oral use against invasive aspergillosis and for mucormycosis. Nowadays, the optimal management of the treatments with triazoles requires the use of Therapeutic Drug Monitoring (TDM), in order to prevent sub-therapeutic or toxic concentrations...

The rapid reaction of the smallest Criegee intermediate, CH2OO, with water dimers is the dominant removal mechanism for CH2OO in the Earth's atmosphere, but its products are not well understood. This reaction was recently suggested as a significant source of the most abundant tropospheric organic acid, formic acid (HCOOH), which is consistently underpredicted by atmospheric models. However, using time-resolved measurements of reaction kinetics by UV absorption and product analysis by photoionization mass spectrometry, we show that the primary products of this reaction are formaldehyde and hydroxymethyl hydroperoxide (HMHP), with direct HCOOH yields of less than 10%...

Some clostridia produce alcohols (ethanol, butanol, hexanol) from gases (CO, CO2, H2) and others from carbohydrates (e.g., glucose). C. carboxidivorans can metabolize both gases as well as glucose. However, its bioconversion profile on glucose had not been reported. It was observed that C. carboxidivorans does not follow a typical solventogenic stage when grown on glucose. Indeed, at pH 6.2, it produced first a broad range of acids (acetic, butyric, hexanoic, formic, and lactic acids), several of which are generally not found, under similar conditions, during gas fermentation...

Paris polyphylla var is an herbal plant herb widely used in Traditional Chinese Medicine. The purpose of this study is to develop an Ultra Performance Liquid Chromatography-tandem mass spectrometer (UPLC-MS) method to quantify the major components (i.e., nine saponins) from P. polyphylla in plasma samples. A UItra BiPh column (100×2.1mm, 5μm) was used with acetonitrile/0.1% formic acid in water as mobile phases. The analytes were quantified using a Waters XEVO TQ mass spectrometer via multiple reaction monitoring (MRM) with positive scan mode...

A liquid chromatography-tandem mass spectrometry method with solid-phase extraction (SPE) was developed and validated for the detection and quantitation of bentazone and its two hydroxylated metabolites, 6-hydroxybentazone and 8-hydroxybentazone, in postmortem blood. Sample cleanup was performed using a hydrophilic-lipophilic balanced (HLB) SPE cartridge and then separated on a C18 LC column using a gradient elution of 0.1% formic acid in distilled water and 0.1% formic acid in methanol. The identification of bentazone and its hydroxylated metabolites was performed using tandem mass spectrometry with electrospray ionization in negative ion mode with selective reaction monitoring...

It was sensation when Dr. J. Beneviste reported alleged experimental biological evidence of the water memory effect (E. Dayenas et al. Nature 333, 816-818, 1988; https://doi.org/10.1038/333816a0). These experiments have never been reproduced in controlled conditions, however. Instead, the hypothesis that water can be imprinted with the memory of past solutes was ruled out (J. Maddox et al. Nature 334, 287-290, 1988; https://doi.org/10.1038/334287a0). At present, so-called "molecular imprinting" is a technology of preparing polymer matrices as affinity-based analyte separation media (J...

Alcohol consumption during pregnancy remains a significant cause of preventable birth defects and developmental disabilities, however, the mechanism of toxicity remains unclear. Methanol is present as a congener in many alcoholic beverages and is formed endogenously. Since ethanol is preferentially metabolized over methanol, it has been found in the sera and CSF of alcoholics. Toxicity resulting from methanol has been attributed to formic acid. Formic acid is present in significantly higher quantities in biofluids of alcoholic patients...

The potential energy surfaces (PESs) and reaction rate constants of the unimolecular decomposition of ethyl formate (EF) were investigated using high-precision theoretical methods at the CCSD(T)/CBS(T-Q)//M06-2x/6-311++G(d,p) level of theory. The calculated PESs of EF dissociation and molecular decomposition reactions prove that the intramolecular H-shift to produce formic acid and ethylene is the dominant decomposition pathway. A detailed chemical kinetic mechanism for EF pyrolysis was constructed by incorporating the important reactions of EF and its radicals into an existing mechanism previously developed for small methyl esters...

An ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry method in both positive and negative ion modes was established in order to comprehensively investigate the major constituents in Wu-Ji-Bai-Feng-Pill. Briefly, a Waters ACQUITY UPLC HSS C18 column was used to separate the aqueous extract of Wu-Ji-Bai-Feng-Pill. 0.1% formic acid in acetonitrile and 0.1% aqueous formic acid v/v were used as the mobile phase. All analytes were determined using quadrupole time-of-flight mass spectrometry with electrospray ionization source in positive and negative ion modes...

Species of Copaifera genus (Fabaceae - Caesalpinoiodidaeae) produces an important commercial oleoresin that displays many medicinal properties. Copaifera oleoresins (COR) are composed mainly of a mixture of diterpenes and sequiterpenes, and the main reported acid diterpenes for this genus are kaurenoic, copalic, hardwickiic and polyaltic acids. An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for identification and quantification of nine acid diterpenes...

Solar-driven photocatalytic conversion of CO2 into fuels has attracted a lot of interest; however, developing active catalysts that can selectively convert CO2 to fuels with desirable reaction products remains a grand challenge. For instance, complete suppression of the competing H2 evolution during photocatalytic CO2-to-CO conversion has not been achieved before. We design and synthesize a spongy nickel-organic heterogeneous photocatalyst via a photochemical route. The catalyst has a crystalline network architecture with a high concentration of defects...

Flower-like LiαTiOx micro/nanostructures were successfully synthesized to degrade 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) at 250-350 °C. The pseudo-first-order kinetics rate constant of the reaction at 300 °C was in the range of 0.034-0.055 min-1. The activation energy was as low as 39.9-48.1 kJ/mol. The excellent performance attained over LiαTiOx was attributed to Li dopant having the electron-donating effect, which enhanced the oxygen specie mobility. The oxidative reaction was believed to be the dominant degradation pathway following Mars-van Krevelen mechanism, being accompanied by the weak hydrodebromination occurrence generating the trace mo- to tri-BDEs...